1. Field of the Invention
The present invention relates to a network apparatus for transmitting/receiving a packet to/from an external apparatus connected thereto via a network, a control method therefor, and a storage medium.
2. Description of the Related Art
Network communication monitoring software used to analyze various communication errors such as a network disconnection and a sequence error in a network communication system in which a plurality of network apparatuses are connected to each other has been developed.
However, a process of connecting a PC provided with such software to a network apparatus each time a network failure occurs and causing the PC to monitor network communication and analyze a communication error is time-consuming and costly.
A technique for rapidly correcting a communication error in a network apparatus without using a PC provided with monitoring software has been proposed. That is, a system for causing a network apparatus to capture a packet transmitted/received via a network and monitor the captured packet is disclosed (see, for example, Japanese Patent Laid-Open No. 2004-362012). It is expected that an increasing number of such apparatuses will be used.
In the above-described monitoring method, if a network apparatus rejects a processing request transmitted from an external apparatus, the fact is output as error information. The reason why the network apparatus rejects the processing request transmitted from the external apparatus is that, for example, the IP address of a request source from which the processing request is transmitted is registered as a rejection IP address to be filtered, or an application of a request destination to which the processing request is transmitted is set to an OFF state.
For example, in a case that the processing request is rejected due to the fact that the IP address of a request source from which the processing request is transmitted is registered as a rejection IP address to be filtered, an application of a request destination to which the processing request is transmitted performs IP address filtering processing. Accordingly, output error information can include information about the application of the request destination to which the processing request is transmitted.
However, if the application (for example, LPD or Raw) is set to the OFF state, the processing request transmitted from the external apparatus cannot be delivered to the application. In this case, the application cannot determine that the processing request has been rejected. Furthermore, if the application is set to the OFF state, the network apparatus cannot monitor a port number corresponding to the application of the network apparatus. In this case, the network apparatus cannot know to which of applications of the network apparatus the processing request has been transmitted.
Accordingly, after the processing request transmitted from the external apparatus has been rejected, it takes a long time to analyze a cause of the rejection. Furthermore, it is difficult for the user of the network apparatus to find a cause of the rejection, which is inconvenient for the user.